An interactive perspective of health education for the tropical disease control: the schistosomiasis case

Some municipalities in Brazil have been requesting orientation for the implementation of health education programs related to the control of schistosomiasis. This demand was based on experiences in the development of health education researches, strategies and materials for school-age children, involving the communities and secretaries of health and education. Motivated by this request and the recently implemented plan of health services (Unified Health System - Sistema Único de Saúde - SUS) that gives autonomy to the municipalities to utilize health resources and services in Brazil, this paper presents an interactive perspective of planning health education research and programs. The purpose of this perspective is to stimulate a reflection on the needs and actions of institutions and people involved in health education research and/or programs to obtain sustainability, commitment and effectiveness - not only in the control of schistosomiasis, but also in the improvement of environmental conditions, quality of life and personal health. This perspective comprises interaction among three levels related to health education programs: the decision level, the executive level and the beneficiary level. The needs and lines of action at each of these levels are discussed, as well as the ways in which they can interact with each other. This proposal may lead to useful interactive ways of planing, organizing, executing and evaluating health education research and/or program, not only towards the prevention and control of the disease at stake, but also to promote health in general.

Epidemiology and Anthropology: an integrated approach dealing with bio-socio-cultural aspects as strategy for the control of endemic diseases

The control of endemic diseases has not attained the desired level of effectiveness in spite of the use of modern efficient thecnologies. The classic interventionist approach for the control of schistosomiasis is centered on systemic control of the snail hosts combined to large scale medical treatment and is usually carried out without social preocupation due to the assisted communities. It is easy to understand the interest and the ethical compromise of public health research while producing studies in which the biological and social determinants as well as the cultural components should be considered and also encompass the historical dimensions and symbolic representations. In face of the recent political decision in favor of decentralizations of health administration to municipal level, we suggest, in the present paper, an integrated approach for the epidemiological diagnosis of an endemic situation at local level. Theoretical and methodological aspects from both, epidemiology and anthropology are discussed. Epidemiological methods can be used to detect the dependent variables (those related to the human infection) and the independent variables (demographic, economic, sanitary and social). Another methodological approach of anthropological /etnographic nature can be conducted in order to make an articulation of the knowledge on the various dimensions or determinant levels of the disease. Mutual comprehension, between researchers and the people under investigation, on the dynamic transmission process would be relevant for a joint construction, at local level, of programmed actions for the control of endemic diseases. This would extend reflections on the health/disease process as a whole.

Different approaches to modelling the cost-effectiveness of schistosomiasis control

This paper reviews three different approaches to modelling the cost-effectiveness of schistosomiasis control. Although these approaches vary in their assessment of costs, the major focus of the paper is on the evaluation of effectiveness. The first model presented is a static economic model which assesses effectiveness in terms of the proportion of cases cured. This model is important in highlighting that the optimal choice of chemotherapy regime depends critically on the level of budget constraint, the unit costs of screening and treatment, the rates of compliance with screening and chemotherapy and the prevalence of infection. The limitations of this approach is that it models the cost-effectiveness of only one cycle of treatment, and effectiveness reflects only the immediate impact of treatment. The second model presented is a prevalence-based dynamic model which links prevalence rates from one year to the next, and assesses effectiveness as the proportion of cases prevented. This model was important as it introduced the concept of measuring the long-term impact of control by using a transmission model which can assess reduction in infection through time, but is limited to assessing the impact only on the prevalence of infection. The third approach presented is a theoretical framework which describes the dynamic relationships between infection and morbidity, and which assesses effectiveness in terms of case-years prevented of infection and morbidity. The use of this model in assessing the cost-effectiveness of age-targeted treatment in controlling Schistosoma mansoni is explored in detail, with respect to varying frequencies of treatment and the interaction between drug price and drug efficacy.

Schistosomiasis control based on repeated chemotherapy in a rural village of the sugar-cane zone in Northeast Brazil

A schedule of repeated chemotherapy with oxamniquine, consisting of biannual treatment of school-aged (7-13 years) children and annual treatment of all other age groups, was used in a representative rural village from a highly endemic area of schistosomiasis in Pernambuco. Significant reductions in infection were obtained only after two cycles of treatment, as the overall prevalence decreased from 72.6% to 41.7% and the geometric mean egg counts per gram of faeces among positives fell from 188.4 to 76. In a school-aged cohort (n=29) three treatments at six-month intervals were necessary to significantly reduce the proportion of positives (from 75.9% to 51.7%). In a cohort of children under 7 years of age (n=20) the proportion of positives actually increased (from 30% to 45%) despite two annual treatments. Water contact was intense and host snail density was relatively high. As there is no short-term perspective of improved sanitation, auxiliary measures such as focal mollusciciding are needed for an adequate control of schistosomiasis in this and alike areas.

LILRB2 interaction with HLA class I correlates with control of HIV-1 infection.

Natural progression of HIV-1 infection depends on genetic variation in the human major histocompatibility complex (MHC) class I locus, and the CD8+ T cell response is thought to be a primary mechanism of this effect. However, polymorphism within the MHC may also alter innate immune activity against human immunodeficiency virus type 1 (HIV-1) by changing interactions of human leukocyte antigen (HLA) class I molecules with leukocyte immunoglobulin-like receptors (LILR), a group of immunoregulatory receptors mainly expressed on myelomonocytic cells including dendritic cells (DCs). We used previously characterized HLA allotype-specific binding capacities of LILRB1 and LILRB2 as well as data from a large cohort of HIV-1-infected individuals (N = 5126) to test whether LILR-HLA class I interactions influence viral load in HIV-1 infection. Our analyses in persons of European descent, the largest ethnic group examined, show that the effect of HLA-B alleles on HIV-1 control correlates with the binding strength between corresponding HLA-B allotypes and LILRB2 (p = 10(-2)). Moreover, overall binding strength of LILRB2 to classical HLA class I allotypes, defined by the HLA-A/B/C genotypes in each patient, positively associates with viral replication in the absence of therapy in patients of both European (p = 10(-11)-10(-9)) and African (p = 10(-5)-10(-3)) descent. This effect appears to be driven by variations in LILRB2 binding affinities to HLA-B and is independent of individual class I allelic effects that are not related to the LILRB2 function. Correspondingly, in vitro experiments suggest that strong LILRB2-HLA binding negatively affects antigen-presenting properties of DCs. Thus, we propose an impact of LILRB2 on HIV-1 disease outcomes through altered regulation of DCs by LILRB2-HLA engagement.

Evaluación de la efectividad del tratamiento mediante instilaciones con ácido hialurónico en el control de la hematuria asociada a cistopatía rádica

Quan la bufeta és exposada a la radiació durant el tractament de tumors pelvians, esdevenen una sèrie de canvis histopatològics amb manifestacions clíniques. A més de la síndrome miccional irritatiu caracteritzat per urgència, polaquiuria i disúria, l'aparició d'hematúria suposa una de més grans les complicacions que l'uròleg ha de manejar. L'àcid hialurònic endovesicals constitueix una de les opcions de tractament. Avaluem l'efectivitat del tractament i la idoneïtat de la seva pauta d'administració mitjançant un estudi descriptiu retrospectiu amb 20 pacients i un període de seguiment mínim de 12 mesos.

Influencia de las técnicas de control del arroz salvaje sobre la población de quironómidos

Las larvas de quironómidos (Cricotupus sylvestris) constituyen la plaga invertebrada más importante que afecta al establecimiento del cultivo en aquellos arrozales donde se realiza siembra directa sobre una lámina de agua. En el delta del Ebro, Catalá MM et al., 2008a y 2008 b, demostraron como largos periodos de inundación favorecen el incremento de la población de larvas de quironómidos, hasta tal punto que se llega a destruir prácticamente la totalidad de semillas y plántulas si coincide el periodo de máxima población de la plaga con el de mayor sensibilidad del cultivo. Los campos de arroz infestados de arroz salvaje (Oryza sativa L.) requieren largos periodos de inundación para favorecer la nascencia del mismo y proceder a su destrucción, que puede ser mecánica o química. Este método de eliminación de arroz salvaje se denomina “falsa siembra”. Por otra parte se sabe que no hay insecticidas autorizados en el cultivo del arroz con suficiente eficacia para controlar las elevadas poblaciones de quironómidos (trabajos no publicados del autor), lo que nos lleva a estudiar la plaga dentro del ámbito agronómico del cultivo para disminuir la misma a niveles poblacionales suficientemente bajos que permitan conseguir una buena densidad de planta. Así pues, este trabajo pretende estudiar el efecto que tienen las distintas técnicas de control del arroz salvaje sobre la población de quironómidos.